Field
The present technology relates to methods and apparatuses for channel stop doping, which can decrease the effect of parasitic transistors and improve the current of small dimension transistors.
Description of Related Art
Small dimension transistors such as finFETs and planar transistors are particularly sensitive to changes in the density of dopants in the transistor channel. Accordingly, a fabrication goal is to decrease or eliminate dopants in the transistor channel.
One approach is to form shallow trench isolation (STI) oxide regions, and then perform high implant energy implants through the semiconductor surface to form the n-wells and p-wells. However, such an approach has the side effect of undesirable channel doping in the surface of the semiconductor, which runs counter to the original goal of decreasing or eliminating dopants in the transistor channel. Such an approach also fails to have abrupt doping junctions between the lightly doped or undoped channel, and the moderately to heavily doped semiconductor material underlying the channel.